1. Technical Field
The disclosure relates to an illumination device. More particularly, the disclosure relates to an illumination device of a light emitting diode (LED).
2. Background
Owing to the characteristics of long life span and low power consumption, a light emitting diode (LED) has been broadly applied to large electronic display bulletins, traffic lights, and direction indicating lights, for instance. The existing LED industry is advancing toward the goal of high brightness and low light loss, such that the LED is able to replace conventional illumination means. Further, the LED will gradually serve as a future projection light source with high brightness; for instance, the LED is applicable to a digital light processing (DLP) projector, a liquid crystal display (LCD) projector, and any other color optical projection device with high brightness.
An exemplary conventional LED illumination device mainly includes a red LED, a green LED, and a blue LED. After the red light emitted from the red LED, the green light emitted from the green LED, and the blue light emitted from the blue LED are mixed, white color can be output. Nonetheless, the light emitted from the existing LED is shaped as a straight line and is not in a scattering state as is the light emitted from a conventional tungsten filament lamp or a conventional fluorescent lamp. The light in form of a straight line can merely be condensed to one point, while other ambient light beams are unable to be condensed. Accordingly, the illumination range is limited, or the brightness easily appears to be insufficient.